Treating slimes from electrolytic refining of lead.



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ANSON GARDNER BETTS, oF'rRoY, NEW YORK.

TREATING SLIMES FROM ELECTROLYTIC REFINIhlG 0F LEAD.

Specification of Letters Patent.

Patented. June 23, 1908.

Application filed December 8, 1906." Serial No. 34639 Slime from the E ectrolytic Refining. of

Load, of which the following is a specifica: tion.

This invention relates to the treatment of anode slime from the electrolytic refining of lead, by direct melting.

The object of the invention is to provide a quick and cheap method.

To carry out my process I oxidize the slime preferably by air which may be done in a preliminary stop either slowly at the ordinary temperature, or more quickly by heating to say 200 to 300 degrees centigrade.

On melting the oxidized or oxidizing slime in a crucible or other suitable furnace, not all the silver will usually be found as metal at the bottom of the melt as antimony peroxids are apt to be present, and these carry the silver into the slaq. l accordingly prefer to add a reducing agent during or before the melting to reduce antimony tetroxid and. antimony pentoxid'to the readily fusible trioxid, which does not oxidize the silver, raw slime being especiallysuitable' as reducing agent.

in such ways as the ahovo i am able to produce a slag carrying most of the lead and antimony and. a dore bullion containing the silver.

/Vhcn bismuth. is present in the slime, the

espmsliy well, and opera- .te, lor n1 a 1-. in. 2 will go into metal, ivhile the lead and an timony are in ei 1 found almost entirely in the s and the silver 2. id gold in the metal. "liho presence of bismuth in the metal is desirable also, because it lowers the limiting point oft e alloy, and permits carrying out the operation at a lower 13111- perature, with less vclatiliza'tion. When sulfur pres nt in the s added, matte, high in copper, duced.

is also proor is purp l Analyses .of such products from a single melting are-- Metal. Matte. Slag. Gold- .78% Silver 65.75% Bismutln"- 20.3 295'} Copper; 5.1 46.3% 1.15% Antimony 1.3 None 28 v Lead .875 34.9

In making the above melt it was not necessary to add a reducing agent, as the slime happened to be oxidized to just the right ex' tent, by the preliminary heating in air that it received. The slag may then be cleaned from some of the bismuth and any gold and silver it may contain, by treating it in the melted condition with a little reducing agent, especially well with a metal as lead or antimony, or a mixture of metals as slime, which precipitates out bismuth, and this carries with it the silver and gold. I

Alter cooling I treat the slime with an acid or mixture of acids to dissolve one of the principal metals lead and antimony present and leave the other, especially preferring the of hydroflnoric and sulfuric acids to dissolve the antimony as fluorid'and coirvert the lead to lead sulfate.

Part of the copper and perhaps traces of silver will dissolve with the hydrofluoric acid treatment, but this can be preci itated out by mean oi metallic antimony, etore elec" trol g singx in treating the slime in m er to I .1 silica possible.

.ea antimony can be treatedhy well- :uown methods for the remaining values.-

l' v hat l.

by Letters Patent is 1. The'process oi treatin anode slime fromv the electrol tic refining of lead, which c0n-- sists in oxidizing the slime andmelting it the solution for metallic antimony. not to use an excessof h oro claim as new and desire to secure lu left after the extraction of the with a reducing. agent to reduce antimony peroxide to trioxid, producing a slag carrying most of the lead and antimony and a dent bullion.

2. The recess of treating 'anode slime from the e ectrolytic refining of lead which consists in oxidising the slime and melting it I let with the addition of u'noxidized or comparatively little oxidized slime as reducing agent, producing a slag carrying most of the lead and antimony and a dor bullion.

3. The process of treating anode slime from the electrolytic refining of lead which consists in oxidizing the slime and melting it with the addition of material containing metallic antimony as reducing agent, producing a slag carrying most of the antimony and lead and an alloy containing the silver and gold. I

4. The recess of treating anode slime from the e ectgolytic refining of lead which consists in oxic izing and melting it to a dor bullion and a slag containing most of the antimony and lead, and treating the slag with an acid or mixture of acids capable of dissolving one only of the two principal metals thereof.

5; The rocess of treating anode slime from the e ectrolytic refining of lead which eonsists'in oxidizing and melting it to a slag containing most of the lead and antimony and an alloy containing the silver and gold, and treating the slag with hydrofluoric acid to remove antimony therefrom.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

ANSON GARDNER BE'ITS.

Vitnesses:

RALPH H. SHERRY, .Y BEN. STAmmoK. 

